Amputees may use a variety of prostheses designed to support their residual limb during ambulation and other activities. The residual limb may include bone, muscle, tissue, and skin. Prosthetic limbs generally include a socket and a liner designed to fit over the residual limb. The socket may be a relatively rigid shell that encases the residual limb. The liner may provide a flexible cushion between the residual limb and socket, and act as a “second skin” between the residual limb and socket. The liner may provide a more consistent connection between the residual limb and the prosthetic socket, and increase the variety of motions an amputee may perform.
Sockets may be made of a variety of materials such as resin, acrylic, carbon fiber, and other suitable materials. Sockets may comprise one or more rigid layers and in some cases a flexible inner socket may be used between the hard socket and liner to provide a better connection with more dynamic linkage between the residual limb and prosthesis. An inner socket may provide greater surface area for connection with a rigid socket, improve the vacuum for vacuum-assisted suspension sockets, and reduce friction against the residual limb.
Sockets and liners are typically constructed from materials that exhibit poor heat transfer properties and are not gas permeable, which results in the wearer's body heat being trapped inside the socket. Thus, despite advances in liners and sockets, there exists an issue of high temperature environments developing in the socket of prosthetic devices. If heat builds up to the point of sweating, the prosthetic wearer is at risk of skin degradation, discomfort, decreased mobility, and poor linkage between the prosthesis and residual limb. This situation necessitates the use of a cooling system to improve amputee comfort and usability of prosthetic devices.
Prosthetic limbs are generally custom made to fit an individual's residual limb by a prosthetist. A prosthetist may evaluate the size and condition of the residual limb, patient health and lifestyle, and other factors in designing a suitable prosthetic. Such design may include a prosthetic cooling system to resolve the temperature problem as previously described. A prosthetist may select a cooling system as described herein for the inclusion in the prosthesis during fabrication. One method of alleviating heat retention is through the application of thermoelectric elements (TEC) to cool the socket. Due to the curved nature of a prosthetic socket and the typical flat planar geometry of TECs, the method of coupling the TEC to the socket requires a specialized TEC-socket interface. Furthermore, for the TEC to be more effective in cooling the residual limb, the wall of the socket may need to be thinned in the area of the TEC Thinning the socket wall in localized areas may weaken the structural integrity of the socket, and increase the possibility of a crack developing. Also, permanently coupling a TEC to a prosthesis socket makes removing the TEC impossible without damaging the socket. If an installed TEC fails, a new socket may have to be fabricated to replace the existing socket with nonworking TECs.
There remains a need for a modular prosthetic cooling system that may be adapted for removable mounting to a prosthetic socket substantially without compromising the structural integrity of the prosthesis socket.